Just recently bought a bottle of Reacta-Clean since I was running low on Tac-Up, anyway I noticed the warning "suspected of causing cancer" on the bottle of Reacta-Clean, never came across a warning like that on past bottles or on any other ball cleaners like Hook-It or C&D before...I do remember on an older bottle of Reacta-Clean saying denatured alcohol being an ingredient...so should I now be putting on a pair of nitrile gloves like a surgeon after every league set to use the cleaner? Sure my fellow bowler's will give me funny looks if I do that! lol

Just recently bought a bottle of Reacta-Clean since I was running low on Tac-Up, anyway I noticed the warning "suspected of causing cancer" on the bottle of Reacta-Clean, never came across a warning like that on past bottles or on any other ball cleaners like Hook-It or C&D before...I do remember on an older bottle of Reacta-Clean saying denatured alcohol being an ingredient...so should I now be putting on a pair of nitrile gloves like a surgeon after every league set to use the cleaner? Sure my fellow bowler's will give me funny looks if I do that! lol

Honestly, all cleaners use some chemical that is harmful to humans, to one degree or another. Yes, every time you clean your ball you should use gloves. More than one of these "active' ingredients is known to have caused cancer by being absorbed thru human skin.

When I use Clean n Dull and Hook-it, I ALWAYS wear some kind of gloves. ALWAYS!

One chemical that makes Denatured Ethyl alcohol denatured is often methyl alcohol, which is very dangerous to humans. Nowadays, there are other denaturing chemicals, whose intent is to make the ethyl alcohol (the alcohol in all alcoholic drinks) undrinkable by humans. Methyl alcohol makes it poisonous.

Other additives that are used to denature Ethyl Alcohol include  isopropyl alcohol, acetone, methyl ethyl ketone, methyl isobutyl ketone, and denatonium (denatonium benzoate -the most bitter chemical compound known).

There was a form of alcohol that I heard to never use on bowling balls because of how it breaks down the coverstock and I cannot remember which one now. Hmm..

I've been using Simple Green as I thought with it mentioned so many times others had already done the homework. But I see now it is quite terrible for human contact. I don't use gloves, but I also don't actually touch it. I set a towel down, set the ball on the towel and spray around the ball. Then with another towel, and use of the finger holes, wipe it down to keep skin contact minimal at worse.

SG has all zeros on the MSDS diamond and is considered non toxic.  They removed 2-Butoxyethanol from it in 2013 which was the only thing really questionable.  It really is safer than virtually any other household cleaner (especially diluted as its meant to be used).  As for affecting the cover stock the USBC wouldn't have made it legal if it changed the cover stock in any way.  I wouldn't drink it or bath in it but compared to something like SuperClean (considered hazardous material) its far safer.  Even 91% iso is considered significantly more toxic.  Still never hurts to take precautions for sure.  The only alcohol that could cause any issues with the coverstock would be ethyl alcohol that is denatured with MEK (the culprit not the alcohol itself, ketones not alcohol are the enemy) which is usually just called denatured alcohol (charlest mentions above as well other things used to denature alcohol).